Create an App for Shopify

We need an app for a subscription system at Shopify. There are 3 different subscription models and we need an app to determine which and how many products can be purchased under the respective subscription model. The subscription models each have a term of one month with automatic renewal, but can be cancelled at any time. The products in the shop can only be purchased if a subscription has been concluded beforehand. If you have reached the maximum number of products in the respective subscription model, an upgrade to a higher-quality subscription should be possible.